When shutting of a piercing valve or saddle valve on a refrigerator or insta hot water feed line, loosen the packing nut first. This will prevent you from twisting off the stem if the valve hasn't been used in a number of years. If stem still tight, then I shut off main water supply to whole house to avoid replacing valve.

Wedgeman, Love this one I don't now how many time I twisted off stems before I learned loosen the packing nut first.. and the opposite work to if can't get the valve to shut off all the way tighten the packing nut...

thanks, Krazytech. Another tip.......so to speak. When shutting off any valve, and your not sure its off, I always carry in a bucket with me. Sometimes, when those piercing valves don't shut off, the stem breaks off or strips and cannot be shut off. You, thinking its off, Loosens the compression nut off of the valve and WHOOSH - Flood. Thats why I always have a bucket so that I can put the line in there and Run and quickly shut off the water main or shove the line back in the valve. I also carry several sizes including a flat 1 foot high bucket to fit the need. Also, in my toolbox, I carry 1/4, 3/8 plugs so in emergency I can screw it into compression nut and shut off water that way.

Another tip - I always use yellow or white electrical tape. If I have to label wires or anything else, I can write with my Black Sharpie on the tape (terminal numbers on motor, timer, switch, etc. ) Makes it easier to change wires on anything instead of switching terminal to terminal.